Described and named in the late 1920's by the psychologist Wolfgang Metzger, the word “Ganzfeld” is used to describe a featureless field of view and has been used to describe conditions that include the visual perception experienced in dense fog, unlit caves, and the cloudless sky. Devices currently in use to create a Ganzfeld include featureless hemispheres as in the Goldmann-Weeks Adaptometer for night vision evaluation, opaque goggles, and bisected ping-pong or tennis balls. Fully opaque contact lenses exist for occlusive treatment of monocular eye conditions such as monocular treatment of amblyopia, extreme photosensitivity in pathology of an eye, and for the treatment of intractable diplopia. Binocular occlusive lenses have been used for theatrical effect.
A “Ganzfeld effect” is a phenomenon of visual perception caused by staring at an undifferentiated and uniform field of color, including black. The effect is a loss of vision, apparent blindness, as the brain cuts off the unchanging signal from the eyes. The Ganzfeld effect may give rise to hallucinations or other psychological effects.
Several patents exist which describe “opaque” contact lenses. The disclosures of these patents are, however, limited to lenses with opaque portions that allow for vision around or through the lenses. Opaque contact lens patents describe cosmetic lenses made to alter the perceived color of the iris of the eye and feature a central transparent aperture to allow vision through the lenses. Monocular fully opaque lenses have been described for treatment of amblyopia and the monocular sensation of intractable photic sensitivity and pain. Some opaque lens patents describe opaque portions of a lens for rehabilitation of visual field loss, or to provide new or multiple apertures for low vision treatment.
Prior art devices used to create a Ganzfeld, such as goggles and hemispheres, offer an incomplete effect due to physical aspects of the goggles or hemispheres used.